Wet chemical oxidation of silicon surfaces prior to the deposition of all-PECVD AlO_x/a-SiN_x passivation stacks for silicon solar cells

摘要

Aluminum oxide (AlO_x) is currently under intensive investigation for use in surface passivation schemes in solar cells. AlO_x films contain negative charges and therefore generate an accumulation layer on p-type silicon surfaces, which is very favorable for the rear side of p-type silicon solar cells as well as the p~＋-emitter at the front side of n-type silicon solar cells. However, it has been reported that quality of an interfacial silicon sub-oxide layer (SiO_x), which is usually observed during deposition of AlO_x on Silicon, strongly impacts the silicon/AlO_x interface passivation properties. The present work demonstrates that a convenient way to control the interface is to form thin wet chemical oxides of high quality prior to the deposition of AlO_x/a-SiN_x:H stacks by the plasma enhanced chemical vapor deposition (PECVD).